How to Prevent Lower Back Rounding During Squats | Butt Wink Prevention

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Why Does My Lower Back Hurt After Heavy Squat Sessions?


It could be because of Lower Back Rounding during deep squats, otherwise know as Posterior Pelvic Tilt or Butt Wink.

It is without a doubt Squats are one of the most quintessential movements needed to strengthen the lower body. Being a versatile compound movement, squats engage more than just your glutes and can be done in a variety of ways. However, with great power comes great responsibility. Utilizing proper form is essential to reduce the chance of injury and to have a more efficient lift.  In this article we uncover everything needed to Prevent Lower Back Rounding during Squats.

What is a Lower Back Rounding?


If your active in the fitness community or simply hang around your local gym, then you have probably heard the term “butt wink” on more than one occasion. Butt Wink in simplistic terms is lower back rounding during deep squats causing unneeded stress on your lumbar. In more advanced terms, Butt Wink or “Posterior Pelvic Tiltis when at the bottom of a squat the pelvis goes through a backwards rotation causing the tailbone to tuck under the body and putting the spine in a flexion position.

How to Prevent Lower Back Rounding During Squats

When performing any movement your lumbar or lower spine can be in one of three positions: Flexion, Neutral and Extension. When carrying a load and having a spine in flexion position, injury is inevitable. Lumbar Flexion increases the chance of lower back injury due to compressive and shearing forces on the spine. In addition, posterior pelvic tilt put athletes at risk for disc herniation or damaging of spinal ligaments.

Controversially, carrying a load with a neutral spine is safe and does not negatively impact strength. It is a common misconception that deep squats can be performed without Butt Winking. When performing deep squats there is a transitionary period between spine extension and a neural spine. During this transition a Butt Wink is nearly impossible to avoid. Even Olympic Power Lifters, Body Builders, or any strength athlete that utilizes full depth squats have a small butt wink when transitioning.


Tight Hami’s Are Not Always the Answer


Another common misconception about the causes of posterior pelvic tilt among athletes is tight hamstrings. Everyone and their mother is claiming that tight hamstrings cause Butt Wink. It is their belief that the hamstrings have less flexibility or length, thus when reaching the bottom of the squat, the pelvis will be pulled forward, tucking under the body, thus creating a Butt Wink. However, lets dive into this notion of hamstring length and flexibility to see if it has any validity.

The hamstrings, with exception of the short head of the biceps femoris, are a bi-articular muscle group which cross both the knee and hip joints, therefor involved in knee flexion and hip extension. When squatting an interesting concept happens that is hard to wrap your head around, Lombards Paradox. Lombards Paradox to be brief, explains that during a squat motion you are shortening the hamstrings at the knee while simultaneously lengthening at the hip. Meaning the hamstring length goes through insufficient change to claim it as the cause for posterior pelvic tilt.

Let’s assume that tight hamstrings could be the cause for Butt Wink. A simple Quadruped Hip Rocker Test will be able to show us if tight hamstrings are the culprit.

Quadruped Hip Rocker Test

This test mimics a conventional squat in the decent phase. If this athlete were to be standing up right, her knees, ankle and hip flexion involved during the decent phase of the squat would be identical. As we can see the athlete was able to go through the entirety of the movement and exhibit no Butt Wink. Thus, hamstrings could not be the sole reason for Butt Wink when standing, as the length-tension relationship between the joints and hamstrings would not have been significantly altered.

This is not to say that tight hamstrings do not play a role in causing posterior pelvic tilt, simply that hamstrings are not the sole proprietor as many athletes today claim they are.


Then What Causes Butt Wink?


Poor Hip Flexibility

If you suffer from tight hips or hip flexors then you could be starting your squat movement in a anterior pelvic tilt position. Anterior Pelvic Tilt or Lower Crossed Syndrome is the postural position when your pelvis is tilted forward. In other words, your butt sticks out making your lower back arch, causing unneeded stress and pain on your lower back.

Here are some of my favorite stretches to loosen up my hips before i start any leg session.

1. Lying Hip Rotations
  • Lie on back with both knees bent.
  • Cross one ankle over the opposite knee.
  • Move in and out of the stretch by rotating the hip in and out.
  • For the hold, use your hand for assistance to press into the knee.
2. Butterfly Stretch
  • Sit up with feet together, moving the knees down toward the ground.
  • Use your hand to press into the ground and move your groin closer to your heels.
3. Pigeon Stretch
  • Start with your front knee bent to a 90-degree angle. The back knee can be as bent or extended as is comfortable for you.
  • Rotate the back hip toward the front heel, and then toward the back foot.
  • Keep the chest up tall, and only bear as much weight as you can comfortably.



Hip Socket Depth

Everyone is built differently, no one human anatomy is alike. This uniqueness is what gives some individuals an advantage and others a disadvantage given a particular setting. For our purposes, Hip Socket Depth is a large factor you need to take into account when deciding how low you should go.

Unlike your hamstrings or hip flexors, hip socket depth is an anatomical variant that cannot be stretched, trained, or altered without medical procedure. In addition, it is one of the main biomechanical influencers in determining the depth of your squat before you essentially run out of ROM and have to shift it to your lower back.

How to Prevent Lower Back Rounding During Squat


In the image on the left, the hip socket is very deep and sturdy, making it a good candidate in producing power at the top of the squat motion. However, due to the depth of the hip socket, bone to bone contact will happen much sooner than the image on the right. This contact creates a much earlier end range of motion causing the athlete to stop higher or to recruit their lower back for added ROM.




Although it may seem a little basic, balance plays a key role in causing Butt Winks. The lack of stabilizer muscles inhibit the athlete from reaching the full depth. Try switching to Front Squats or Goblet Squats. Typically, Athletes using Anterior Loads (Front Squats) can reach a deeper squat because the movement forces you to have a tall spine and open hips.

How to prevent lower back rounding during squats

If the problem is Anterior-Posterior Stability then try this routine:

  • Hold a dumbbell in a goblet position and squat as low as possible.
  • When you get to the bottom of your squat, unload the weight and don’t let your posture or position change.
  • Once you’ve let go of the weight and you’re comfortably in the bottom of a squat position, stand up. You just did a squat from full depth.
  • Pick the weight up and repeat

This routine trains the hips to drop more downward than backward, which improves mobility and minimizes butt wink.

Ankle Mobility

Ankle mobility more specifically ankle dorsiflexion is huge factor in performing deep squats. In order to go into deep hip flexion you need roughly 15-20 degrees on ankle dorsiflexion. Without proper ankle dorsiflexion as you descend into your squat and the ankle lock up, the body has no other option but to lean forward and compensate by using the lumbar, causing posterior pelvic tilt.

Due to lack of ankle mobility you might want to look into getting yourself a pair of lifting shoes. Weight lifting shoes have a heel lift that alters the body’s center of gravity, allowing the knees to migrate forward to a greater extent.

Lack of Glute Activation

Due to attachment points the glutes have a bigger role on the femoral head and controlling it. The stronger/better your glute activation is the more rearward pull on the femoral head, which in turn will help clear more space to squat a bit deeper. This is why it is important to do glute dominant movements when performing leg day. For example, barbell hip thrust, kettle bell swings and glute bridges are all great movements to work your glutes.


Wrap Up


Squatting is a necessity if you want to build a stronger lower body. However, with great power comes great responsibility. With the cues and tips listed above you have everything you need to reduce the risk of injury from lower back rounding during your squat sessions.

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